Sash windows are becoming even more popular. In a relatively standard or conventional sash window set up, two sash window members are located in side by side window channels of a window frame. The sash window members move up and down relative to one another. The weight of each sash window member is effectively counterbalanced by some type of a balancing mechanism. The outer sash window member can be tilted outwardly for cleaning the outside of both of the window members.
Coil springs are now being used as sash balances. These coil springs are supported at one end within the window jamb or frame and secured at the other end to a balance shoe which travels up and down with the sash window. As the coil spring is unwound, it counterbalances the weight of the window.
It is known to provide sash balance shoes which include rotatable cams to allow outward tilting of a sash window. When the window is tilted outwardly the balance shoe moves to a braking positions to prevent up and down movement of the window holding it in a fixed position for cleaning and the like.
Different examples of balance shoes are shown in U.S. Pat. Nos. 3,789,549, 4,068,406, 4,079,549, 4,271,631, 4,363,190, 4,590,708, 4,610,108, 4,683,676 and 4,718,194. However, all of the structures shown in the above patents are relatively complex and include numerous different working parts subject to wear and premature breakdown. Furthermore, many balance or brake shoes produce relatively inaffective braking action such that the sash windows themselves are then subject to damage.
As a further drawback, the balance shoes of the prior art structures are not constructed to take into consideration possible disconformities in the window jamb which might cause a binding action on the shoe which then makes it harder to move the window.